The present invention relates to an electrical connector for a circuit board, which is to be disposed on a mounting surface of a circuit board.
In a conventional electrical connector for a circuit board (hereinafter also simply referred to as a connector), so-called a floating configuration may be employed. With the floating configuration, even when the conventional electrical connector is displaced from a normal fitting position for fitting to a mating connector in a direction parallel to the mounting surface of the circuit board, terminals of the conventional electrical connector are able to deform in the displacement direction to absorb the displacement. Therefore, it is achievable to fit and connect the conventional electrical connector to the mating connector.
For example, Patent Reference has disclosed a conventional connector that can float in one direction (lateral direction) that is horizontal to the mounting surface. The conventional connector is fitted to connect to a mating connector thereof, having an up-and-down direction as a fitting direction thereof that is perpendicular to the mounting surface of the circuit board.
Patent Reference: Japanese Patent Application Publication No. 2010-003651
The conventional connector disclosed in Patent Reference includes a plurality of terminals, stationary members, and inserting members. The plurality of terminals is made from a metal strip piece by bending the metal strip piece in a sheet thickness direction thereof. The plurality of terminals is arranged in two rows and is held all together with the stationary members and the inserting members, which are respectively disposed at two positions in the longitudinal direction of the terminals.
In the conventional connector disclosed in Patent Reference, each of the terminals is made simply by bending the sheet metal piece into an L-shape in the sheet thickness direction at one end thereof in the longitudinal direction. Each of the terminals has a connecting portion (a portion extending in a lateral direction) at one end thereof and a contact portion (a portion extending in a longitudinal direction) at the other end thereof. The connecting portions are connected to a circuit portion of the mounting surface. The contact portions contact with mating terminals, which are provided in the mating connector, at their sheet surfaces.
In the conventional connector disclosed in Patent Reference, the stationary members do not displace relative to the circuit board and hold all the terminals arranged in the two rows together at positions close to the connecting portions. The inserting members are parts to be inserted in receiving concave portions provided in the mating connector. The inserting members are provided being away from the stationary members in the fitting direction. The inserting members can displace linearly in the lateral direction relative to the stationary members. The inserting members hold all the terminals arranged in two rows with the terminal attachment portions provided in the middle parts in the connector fitting direction. The inserting portions hold the terminals at positions near the contact portions between the parts held by the stationary members and the contact portions.
In the conventional connector disclosed in Patent Reference, each of the terminals has a deformable portion, which can elastically deform in a sheet thickness direction thereof. The deformable portions are parts to be exposed between the parts held by the terminal attachment portions of the inserting members and parts held by the stationary members. In other words, the deformable portions are parts that are held by neither the inserting members nor the stationary members. By the elastic deformation of the deformable portions, the inserting members as well as the contact portions of the terminals displace linearly in the lateral direction relative to the stationary members.
According to the conventional connector disclosed in Patent Reference, when there is misalignment in the lateral direction between the connector and the mating connector, in the connector fitting step, the contact portions of the terminals of the connector receive a pressing force in the receiving concave portions of the mating connector. The pressing force works in the lateral direction from the mating terminals so as to push towards the regular fitting positions. The strength of the pressing force to receive depends on the amount of the displacement. As a result, the deformable portions of the terminals in the two rows, which are all held together by the inserting members, elastically deform in the sheet thickness direction according to the displacement.
At this point, according to the conventional connector disclosed in Patent Reference, the two terminals are held together at two positions by the stationary member and the inserting member in the longitudinal direction of the terminals. Therefore, the inserting members displace linearly in the lateral direction with the contact portions of the terminals in two rows, without tilting to the longitudinal direction. The linear displacement of the inserting members brings the inserting members to the positions, so as to be able to fit the connector to the mating connector. As a result, the connector can fit to the mating connector.
In case of the conventional connector having the floating configuration, when it is achievable to secure large floating (the amount of possible displacement corresponding to the amount of the misalignment) between the connectors, it is achievable to absorb the influence of the misalignment between the connectors, which is preferred. In case of the conventional connector disclosed in Patent Reference, in order to obtain floating with large displacement, the lengths of the terminals may be increased in the fitting direction so as to increase the elastic displacement of the deformable portions of the terminals in the sheet thickness direction. However, by increasing the lengths of the terminals, the size of connector is also increased, so that it is not preferred.
In addition, according to another configuration disclosed in Patent Reference, each of the terminals has a deformable portion in the middle part thereof in the longitudinal direction. The deformable portion is bent to have a 90-degree rotated S-shape. The deformable portion can elastically deform in the sheet thickness direction of the terminal. With such deformable portions having the 90-degree rotated S-shapes, it is achievable to secure large floating by increasing the total length of each of the terminals but without increasing the height dimension of the terminals. As a result, it is not necessary to increase the height dimension of the connector.
When such deformable portions are provided, however, although it is achievable to avoid an increase in the height dimension of the connector, the size is increased in the lateral direction (a direction horizontal to the circuit board) for the amount of bending made in the deformable portions to have the 90-degree rotated S-shapes. Such an increase in the size of the connector in the lateral direction reduces an area of a space for mounting other electronic devices on the mounting surface of the circuit board. As a result, there is less flexibility in the design, and it is not preferred.
Moreover, the terminals are bent to the 90-degree rotated S-shapes, and thereby the terminals have complicated shapes. The complicated shapes of the terminals increase the cost and labor upon manufacturing of the terminals. In addition, since the signal transmission path is curved, for example, when signals to be transmitted between the connectors are high-speed signals, there is concern of adverse impact on the signal transmission speed.
In view of the above problems, an object of the invention is to provide an electrical connector for a circuit board, whereby it is achievable to secure large floating of the terminals without complicating the shapes of the terminals.
Further objects and advantages of the present invention will be apparent from the following description of the present invention.